Presently magnification variable copying machines are proposed which include not only those for producing life-size copies but also copies of specified varying magnifications and those having the function of steplessly varying magnification as desired.
The magnification of these copying machines is expressed as linear magnification which is the ratio of the length of a line after copying to the length of the line before copying. However, when copies are actually handled, for example, for edition or other purposes, the area magnification which is the ratio of an area after copying to the area before copying sometimes appears more convenient than the linear magnification. For instance, when A4 size is to be magnified to A3 size having twice the area of the former, the magnification may be set to a simple value of X2 when in area measurement but needs to be set to X1.414 if it is a linear magnification. Thus, the procedure of setting the magnification to X1.414, although the area is to be magnified twofold, appears awkward and unnatural.